Electrically powered outdoor lighting systems are used to illuminate pathways, yards, parks and other like outdoor areas for security or decorative purposes. Such lights are commonly connected to public utility systems or similar sources of electrical power, and are controlled by preset timing devices to illuminate desired areas at nightfall and automatically turn off at a predetermined time, for example, prior to daybreak.
Many conventional lighting devices require extensive cabling, suitable timing mechanisms and the like, and are relatively expensive to install and maintain. In addition, such lighting devices utilize electric power generated in a conventional manner such as by burning fuel. Burning fuel contributes to contamination of the environment and depletion of existing fuel resources.
More recently, self-contained solar powered illumination devices have utilized photovoltaic devices to charge batteries which, in turn, activate a light source contained therein, in the absence of sunlight, for illumination and/or decorative purposes. Such self-contained devices are desirable because they are relatively inexpensive and require very little maintenance.
Traditionally, such self-contained solar powered illumination devices have a rigid configuration constructed to be anchored in the earth at predetermined locations where illumination is desired. The rigid configuration provides illumination in a fixed spherical area surrounding the solar powered device. Such self-contained solar powered illumination devices are not configured to allow mounting to exterior walls or the roof of a building to provide illumination.
Moreover, the photovoltaic arrays are disposed at the top of prior solar powered illumination devices making it necessary for such an illumination device to be positioned to receive sunlight directly on its top surface during daylight hours.
In addition, prior self-contained devices have limited battery power and thus, typically utilize low wattage bulbs, particularly incandescent bulbs which do not generate sufficient light to provide clear illumination in the areas desired. Incandescent bulbs provide a low level of light and render such self-contained illumination devices particularly impractical for security applications. Alternatively, if sufficient illumination is provided, the battery power is insufficient to maintain the illumination for the time desired.
Thus, although such solar powered illumination devices have been known to serve their purpose, they have not proven to be entirely satisfactory.